BROWN-SÉQUARD IS known eponymously for the syndrome of hemisection of the spinal cord, but most clinicians are not familiar with his colorful, quixotic, and eccentric life history. His contributions to medicine and neuroscience reached much further than his discovery of the spinal hemisection syndrome. He lived in five countries on three continents and crossed the Atlantic 60 times, spending a total of almost 6 years on the sea. He contributed more than 500 papers in his lifetime, was even the editor of many prestigious journals, and spent his last years as Professeur au Collége de France, a most coveted position for a French neuroscientist. Many are not aware of his contributions to endocrinology and hormone replacement therapy, even those who consider him the father of modern endocrinology. Brown-Séquard was a skillful experimentalist. He pioneered the concept of the advancement of neuroscience through experimental physiological observation. He was devoted to science. He was not interested in monetary gains through his inventions or patient care. Although he may be criticized for arriving at some incorrect conclusions from his experiments, his visionary ideas and prescient statements have stood the test of time; he truly was an eccentric genius. This article highlights Brown-Séquard's life history, specifically his time in France and North America, and his contributions to neuroscience and endocrinology.